Diazinium quaternary salts



United States Patent Ofilice 3,030,365 Patented Apr. 17, 1962 3,030,365(PYRIMIDYLMETHYL) DIAZINIUM QUATERNARY SALTS Edward F. Rogers,Middletovm, and Robert L. Clark, 'Woodbridge, N.J., assignors to Merck &Co., Inc.,

Rahway, N.J., a corporation of New Jersey No Drawing. Filed Feb. 2,1960, Scr. No. 6,105 10 Claims. (Cl. 260-2564) NH: b are provided,wherein R is a lower alkyl radical, R is selected from the groupconsisting of and R" is a lower alkyl radical, n has a value of -3inclusive, X is an anion, and b and c are positive numbers having valuessuch that the positive charge of b moles of cation is neutralized by cmoles of anion X. Thus, for example, when X is a monovalent anion suchas a halide, b is 1 and c is 2. When more than one lower alkyl group ispresent in the quaternary salt, such lower alkyl groups need not be thesame in any particular compound. It has been found that such compoundshave useful medicinal properties and are particularly suitable for usein the treatment and prevention of coccidiosis in poultry.

With further regard to Formula I, the anion (designated as X) may be aninorganic anion such as chloride, bromide, iodide, nitrate, sulfate,phosphate, and the like, or the anion of an organic acid such as citric,tartaric, acetic, picric, stearic, succinic, benzoic, phthalic,phenoxyacetic, embonic, abietic, Z-naphthalene sulfonic, orethylenediamine tetraacetic acids. It may also be the anion of a polymersuch as polyphosphate or polystyrenesulfonate ion. The nature of theanion is not critical and any anion may be employed as long as it is notunduly toxic for poultry. However, the anions of the mineral acids andstrong organic acids are preferred. It will be realized by those skilledin this art that an acid addition salt of the primary group present inthese compounds will also be formed concurrently with the quaternarysalt. Accordingly, it is to be understood that the expression quaternarysalt is being used in this specification and claims to mean the acidaddition salt of such quaternary salt.

The compounds of this invention are prepared by reacting an acidaddition salt of an ester of a 2-lower alkyl-4- amino-S-hydroxymethylpyrimidine and a strong acid with a diazine or alkylated diazinecompound. According to the preferred process, an acid addition salt ofan ester of a 2-lower alkyl-4-amino-5-hydroxymethyl pyrimidine and ahydrohalic acid is reacted directly with the diazine or alkylateddiazine compound. This process may be represented as follows:

1 CHZR, 2X

4- NH: N H3 where R is a lower alkyl radical, R is selected from thegroup consisting of and )n N N it is selected from the group consistingof (R) n EN and . (RI!) n R is a lower alkyl radical, n is 0-3 inclusiveand X is a halogen such as chlorine or bromine.

Although the proportions of reactants are indicated to be equimolar inthe above equation such proportions are not critical and an excess ofeither reactant can also be suitably reacted. Preferably, however, anexcess of the diazine or alkylated diazine reactant is employed.

The reaction is preferably but not necessarily carried out in thepresence of an organic solvent which is inert under the reactionconditions. Illustrative of the solvents which may be employed as thereaction medium are the lower alkanols, such as methanol, ethanol,propanol and the like, acetonitrile and the N,N-diloweralkylalkanoamides. The reaction temperature is not critical and it ispreferred to carry out the process at about room temperature. At roomtemperature the reaction is generally complete after from 5-20 hours ormore according to the concentration of reactants and particularreactants employed. However, appreciable amounts of the product areobtained after a short period of time. The products precipitate out fromthe reaction mixture on standing at room temperature or on the additionof a suitable precipitant such as ether, ethyl acetate and the like andcan be recovered by filtration or other conventional techniques.

Although the acid addition salt of the S-hydroxymethyl pyrimidine estersof hydrohalic acids, i.e., the halomethyl pyrimidine dihydrohalides, arepreferably employed for reaction with the diazine or alkylated diazine,the acid addition salt of the S-hydroxymethyl pyrimidine esters of otherstrong inorganic acids such as nitric, phosphoric,

C3 sulfuric. and the like may be used. In addition the quaternizationmay also be brought about employing the acid addition salt of theS-hydroxymethyl pyrimidine esters of strong organic acids such as themethyl sulfinate, ptoluenesulfonate, benzenesulfonate andnaphthalenesulfonate esters.

The quaternization may be conducted so that the particular salt desiredis obtained directly or the quaternary salt recovered from the reactionmedium may be conveniently metathesized to the desired salt bytechniques known in the art.

Among the 1-(2-lower alkyl-4-amino-5-pyrimidylmethyl)-diazinium andlower alkylated diazinium quaternary salts which may be formed accordingto the present invention are the1-(2-methyl-4-amino-5-pyrimidylmethy1)-2-ethyl pyridazinium salts,l-(2-ethyl-4-amino-5-pyrimidylmethyl)-pyridazinium salts,l-(2-n-propyl-4-amino--pyrimidylmethyl)-4-ethyl pyridazinium salts,1-(2- ethyl-4-amino-5 -pyrimidy1methyl -4,6-dimethyl pyrimidinium salts,1-(2-n-propyl-4-amino-5-pyrimidylmethyl)-4- ethyl pyrimidinium salts,1-(2-rnethyl-4-amino-5-pyrimidylmethyl)-pyrimidinium salts,l-(2-ethyl-4-amino-5-pyrimidylmethyl)-4-n-propyl pyrimidinium salts,1-(2-ethyl- 4-amino-S-pyrimidylmethyl)-2-methyl pyrazinium salts, 1-(2-methyl-4-amino-5-pyrimidylmethyl)-2,5 dimethyl pyrazinium salts, and1-(2-n-propyl-4-amino-5-pyrirnidylmethyl)-4-ethyl pyrazinium salts.

As previously indicated herein, the compounds of this invention areuseful in the treatment and prevention of coccidiosis in poultry. Thesecompounds are conveniently fed to poultry as a component of the feed ofthe animals although they may also be given dissolved or suspended inthe drinking water. According to one aspect of the invention,novel..compositions are provided in which a diaziniurn quaternary saltis present as an active anticoccidial ingredient. Such compositionscomprise the quaternary salts intimately dispersed in or admixed with aninert carrier or diluent. By an inert carrier is meant one that isnon-reactive with respect to the quaternary and that may be administeredwith safety to the animals. The carrier or diluent is preferably onethat is or may be an ingredient of the animal feed.

The compositions which are. a, preferred feature of the invention arethe so-called feed supplements in which the active ingredient is presentin relatively large amounts and which are suitable for addition to thepoultry feed directly or after an intermediate dilution or blendingstep. Examples of carriers or diluents suitable for such compositionsare solid orally ingestable carriers such as distillers dried grains,corn meal, citrus meal, fermentation residues, ground oyster shells,Attapulgus clay, wheat shorts, molasses solubles, corn cob meal, ediblevegetable substances, toasted dehulled soya flour, soybean mill feed,antibiotic m-ycelia, soyagrits, crushed limestone and the like. Thequaternary salts are intimately dispersed or admixed throughout thesolid inert carrier by. methods such as grinding, stirring, milling ortumbling. By selecting proper diluents and by altering the ratio ofcarrier to active ingredient, compositions of any desired concentrationmay be prepared. Formulations containing from about 1% to about 40% byweight, and preferably from about 225% by weight of active ingredientare particularly suitable for addition to poultry feeds, andcompositions containing from about 5 l5% by weight of coccidiostat arevery satisfactory. The active compound is normally dispersed ormixeduniformly in the diluent but in some instances may be, sorbed onthe carrier. The optimal concentration of coccidiostat in these feedsupplements will. depend. to some extent on, the. particular compoundemployed. Since it is convenient for the. feed manufacturer to use aboutone pound of feedv supplement for each ton of finished feed, thepreferred concentration of any one of our coccidiostats in a feedsupplement ispartly a function of the level of active ingredient desiredin the finished feed.

Corn distillers dried grains 90.0

C. 1-(2-ethyl-4-amino-5 pyrimidylmethyl)-pyridazinium chloridehydrochloride 15.0 Wheat standard middlings 85.0

D. 1-(2-methyl-4-amino 5-pyrimidylmethyl) 2,5-

dimethyl pyrazinium bromide hydrqbrornide 2 0.0

Corn germ meal 30.0 Corn distillers grains 50.0

E. 1-(2-methyl-4-amino 5 pyrimidylrnethyl)2- ethyl pyradazinium sulfate12.0 Molasses solubles 88.0

F. 1-(2-n-propyl 4-amino 5-pyrimidylmethyl)-4- ethyl pyrimidiniumembonate 5.0 Fermentation residues 50.0 Wheat shorts 45.0

G. 1-(2-n-propyl-4-amino 5 pyrimidy1methyl)-4- ethyl pyridaziniumchloride hydrochloride 40.0 Ground oyster shells 60.0

These and similar feed supplements are prepared by uniformly mixing thediazinium quaternary saltwith the carrier or carriers.

The feed supplements of the type illustrated hereinabove are usuallyfurther diluted. with materials such as corn meal or soybean meal beforebeing incorporated in the animal feed. In this intermediate processingstep the level of coccidiostat in. the carrier is brought down to fromabout 0.1% to about 1.0% by weight. This dilution serves to facilitateunform distribution of the substance in the finished feed. The finishedfeed is one that contains a source of fat, protein, carbohydrate,minerals, vitamins and other nutritional. factors.

The amount of diazinium quaternary salt required for optimum control ofcoccidiosisin poultry will, of course, vary somewhat with the specificcompound or compounds employed. effective when administered inconcentrations of about 0.0125 to 0.1% in the diet; For-most.satisfactory results from the standpoint of both. efiicacyv andincidence of undesirable side effectsit is preferred that the poultryfeed contain between about 0.02% and. 0.05% by weight of diazinium salt.When the diaziniurn, salts are to be employed' as thereapeutic agents,thehigher. concentrations.

poultry by way of the drinking water of the birds. This;

method of treatment is. often employed in the therapeutic meet ourcompounds since poultry with coccidiosis are apt to consume less; solidfeed than normal birds. The

water-soluble quaternary salts, may be added directly. to.

the drinking water. Alternatively, water-soluble powders may beprepared, in, which the. coccidiostat is intimatelyadrnixed with asuitable carrier, such as dextrose or sucrose, and these powders addedto the drinking water of poultry as necessary. may contain any. desired.concentration of .coccidjostat; and preparations containing from 125% byweightof active compound are suitable.

In general, the compounds ofFormula I are Such Water-soluble powdersi..." in...

The following examples are added to illustrate the production ofspecific compounds provided by this invention but it is understood thatthe invention is not to be restricted thereby to the embodimentsdisclosed in these examples.

EXAMPLE 1 1 (2-Ezhyl-4-Amin o-5-Pyrimidylmethyl -Pyridazinum Bromide Hydrobromide To a stirred suspension of 19 g. of 2-ethyl-4-amino-5-pyrimidylmethyl bromide dihydrobromide in 100 ml. of acetonitrile isadded 9 g. of pyridazine. There is a slight warming and the solid goesinto solution. After a few minutes solid particles ofl-(2-ethyl-4-amino-5-pyrimidylmethyl)-pyridazinium bromide hydrobromidebeing to appear. After allowing the mixture to stand at room temperaturefor 18 hours the solid material is collected by filtration, washed withacetone and crystallized from 100 ml. of warm methanol and 400 ml. ofacetone. The crystalline1-(2-ethyl-4-amino-5-pyrimidylmethyl)-pyridazinium bromide hydrobromidethus obtained has a melting point of 265 C. (dec.).

EXAMPLE 2 1-(Z-Ethyl-4-Amino-S-Pyrimidylmethyl)-4,6-DimethylPyrimidinium Bromide Hydrobromide To a mixture of 2 g. of2-ethyl-4-amino-5-pyrimidylmethyl bromide dihydrobromide in ml. ofacetonitrile is added 2 g. of 4,6-dirnethyl pyrimidine. The mixturebecomes Warm and a clear solution is obtained. After allowing themixture to stand overnight at room temperature the solid particles of1-(2-ethyl-4-amino-S-pyrimidylmethyi)-4,6-dimethyl pyrimidinium bromidehydrobromide which form are collected by filtration and crystallizedfrom 4 ml. of methanol. The crystalline 1-(2-ethyl-4-amino-5-pyrimidylmethyl)-4,6-dimethyl pyrimidinium bromidehydrobromide thus obtained has a melting point of 235236 C. (dec.).

EXAMPLE 3 1-(2-Ethyl-4-Amino-5-Pyrimidylmethyl) -2-Meth'yl PyraziniumBromide Hydrobromide T o a stirred suspension of g. of2-ethyl-4-amino-5- pyrimidylmethyl bromide dihydrobromide in 150 ml. ofacetonitrile is added ml. of Z-methyl pyrazine. In a short time crystalsof 1-(2-ethyl-4-amino-5-pyrimidylmethyl)-2-methyl pyrazinium bromidehydrobromide begin to appear. After stirring the mixture for 2 hours andthen allowing the mixture to stand at room temperature for 18 hours thecrystalline material is collected by filtration. The crystallinematerial thus obtained is suspended in 100 ml. of warm methanol andsufficient water is added slowly to form a solution. Acetone is thenadded and the recrystallized product of1-(2-ethyl-4-amino-5-pyrimidylmethyl)-2-methyl pyrazinium bromidehydrobromide having a melting point of 217 C. (dec.) is recovered byfiltration.

EXAMPLE 4 1 -(2-Methyl-4-Amino-S-Pwimidylmethyl) -2,5-DimethylPyrazinium Bromide Hydrobromide To a solution of 25 g. of2-methyl-4-amino-5-pyrimidylmethyl bromide dihydrobromide in 75 ml. ofmethanol is added 65 ml. of 2,5-dimethyl pyrazine. After allowing themixture to stand at room temperature for 1 hour, 200 ml. of ethylacetate is added and the resulting mixture allowed to stand at roomtemperature for an additional hours. The solid particles of1-(2-methyl-4-amino-5- pyrimidylmethyl)-2,5-dimethyl pyrazinium bromidehydrobromide which form are then collected by filtration, The solidmaterial thus obtained is then dissolved in 100 ml. of hot methanolcontaining a small amount of water and recrystallized by the addition ofabsolute alcohol. Resultant l-(2-methyl-4-amino-5-pyrimidylmethyl)-2,5-

dimethyl pyrazinium bromide hydrobromide having a melting point of 241C. (dec.) is recovered by filtration.

EXAMPLE 5 1 -(2-n-Pr0py l-4-Amino-5-Pyrimidylmethyl) -4-EthylPyrimidinium Chloride Hydrochloride 1.9 g. of p-toluene sulfonylchloride is added gradually with shaking to a cooled (05 C.) solution of1.7 g. of 2-n-propyl-4-amino-5-hydroxymethyl pyrimidine in 10 ml. of4-ethyl pyrimidine. The reaction mixture after standing three hours inan ice bath and 15 hours at room temperature, is evaporated in vacuo.The residue remaining is then dissolved in 20 ml. of water, acidifiedwith hydrochloric acid and poured over a column of Amberlite IRA40.0 ionexchange resin on the chloride cycle. Amberlite IRA-400 (available fromthe Rohm & Haas Co., Philadelphia, Pa.) is a strongly basic anionexchange resin containing from 3 to 5% divinylbenzene and may beprepared in the manner described in the example of US. Pat. No.2,591,573. The eluate is then evaporated to dryness yielding1-(2-n-propyl-4-amino-5- pyrimidylmethyl)-4-ethyl pyrimidinium chloridehydrochloride.

EXAMPLE 6 200 mgs. of 1-(2-ethyl-4-amino-5-pyrimidylmethyl)-2- methylpyrazinium bromide hydrobromide is dissolved in 0.8 ml. of concentratedhydrochloric acid. This solution is then carefully diluted with acetoneto precipitate the chloride hydrochloride. This salt is then dissolvedin 0.5 ml. of concentrated hydrochloric acid and the solution slowlydiluted with about 8 ml. of acetone. The 12-ethyl-4-amino-5-pyrimidylmethyl) -2-methyl pyrazinium chloridehydrochloride is then recovered by filtration and dried to constantweight.

EXAMPLE 7 When the quaternary salts of Examples 1, 2 and 4 are treatedwith hydrochloric acid by the method of Example 6, the correspondingchloride hydrochloride quaternary salts are obtained.

EXAMPLE 8 The 2-lower alkyl-4-amino-5-halomethyl pyrimidines employed inmaking the quaternary compounds of this invention are prepared bymethods described in the literature or in the following manner:

A. 2-l0wer alkyl-4-amino-5-cyanopyrimidine.A slurry of 54.7 grams ofbuytramidine hydrochloride and 55 ml. of absolute ethanol is treated atabout 5 C. with a solution of 11 grams of sodium in 220 ml. of absoluteethanol. The resulting solution is added with stirring at 10-12" C. overa thirty minute period to 53.7 grams of ethoxymethylenemalononitrile in54 ml. of absolute ethanol. The resulting mixture is stirred at 0 C. forsix hours and then at room temperature for about 12 hours. The mixtureis then filtered, evaporated to dryness in vacuo and the residue treatedwith water. The alcoholic and aqueous solution precipitates arecombined, washed with water and dried in air. The product isrecrystallized from alcohol to give 2-n-propyl-4-amino-5-cyanopyrimidine.

When the above reaction is carried out with acetamidine there isobtained 2-methyl-4-amino-5-cyanopyrimidine. When propionamidine isemployed as starting material the end product is2-ethyl-4-amino-5-cyanopyrimidine.

B. 2-l0wer alkyl-4-amino-5-aminomethyl pyrimidine dihydrochloride.16.2grams of 2-n-propyl-4-amino-5- cyanopyrimidine is reduced at about 40lbs. pressure in 200 ml. of methanol in the presence of 26 grams ofammonia and one tablespoon of Raney nickel. The drop in pressure isabout 36.5 lbs. The reaction mixture on completion of the reduction isconcentrated to a syrup after filtering otf the catalyst. The residuethus obtained is acidified with dilute hydrochloric acid andconcentratedto a crystalline mass. On recrystallization frommethanol-acetone there is obtained 2-n-propyl-4-amino- S-aminomethylpyrimidine dihydrochloride.

When the 2-methyl and 2-ethyl-4-amino-S-cyanopyrimidines obtained asdescribed above are used as starting materials in this reduction, thereare obtained respectively 2-methyl-4-amir1o-5-aminomethyl pyrimidinedihydrochloride and 2-ethyl-4-arnino-S-arninomethyl pyrimidinedihydrochloride.

C. 2-l0wer alkyl-4-amino-5-hydroxymethyl pyrimidine.TWelve grams of2-n-propyl-4-amino-S-aminomethyl pyrimidine dihydrochloride in 50 m1. ofWater is treated at 50-60 C. with a solution of 3.5 grams of sodiumnitrite in 30 ml. of water. The sodium nitrite is added dropwise over a45 minute period. The heating is continued for an additional two hours,and the reaction mixture then made alkaline with sodium carbonate andextracted with butanol. The butanol extract is evaporated to dryness andthe residue crystallized from acetone to give2-n-propyl-4-amino-5-hydroxymethyl pyrimidine.

When the 2-methyl and 2-ethyl-4-amino-5-aminomethyl pyrimidinedihydrochlorides obtained as in Part B above are utilized in thisreaction in place of the 2- n-propyl compound, there are obtained2-methy1-4- amino-S-hydroxymethyl pyrimidine and 2-ethyl-4-amino-S-hydroxymethyl pyrimidine.

D. 2 lower alkyl 4 amino 5 bromomethyl pyrimidine.The2-n-propyl-4-amino-5-hydroxymethyl pyrimidine obtained in Part C aboveis dissolved in 15 ml. of acetic acid saturated with hydrogen bromide,and the mixture allowed to stand at room temperature for about 15 hours.2-n-propyl-4-amino-5-bromomethyl pyrirnidine dihydrobromide crystallizesand is recovered by filtration and Washed With ether. The material issubstantially pure and may be used directly in preparing the quaternarysalts of this invention.

The other 2-lower alkyl-4-amino-5-hydroxymethyl pyrimidines describedabove are treated in like manner with hydrogen bromide to give2-methyl-4-amino5- bromomethyl pyrimidine dihydrobromide and 2-ethyl-4-amino-5-bormomethyl pyrimidine dihydrobromid'e.

Any departure from the above description which conforms to the presentinvention is intended to be included within the scope of the claims.

What is claimed is:

1. A compound having the structural formula wherein R is a lower alkylradical, R is selected from R is, a lower alkyl radical, n has a valueof 0-3 inclusive, X is a non-toxic anion and b and c are positivenumbers having values such that the positive charge of b moles of cationis neutralized by c moles of anion X.

wherein R is a lower alliyl radical and n has a value of 0-3 inclusivewith an acid addition salt of a 2-lower alkyl-4-amino-5-hydroxymethylpyrimidine ester of a strong acid to form a compound having thestructural formula l N\/ 123 PX- wherein R is a lower alkyl radical, Ris selected from the group consisting of R and n are as previouslydefined, X is an anion, and b and c are positive numbers having valuessuch that the positive charge of b moles of cation is neutralized by cmoles of anion X.

and

References Cited in the file of this patent UNITED STATES PATENTS2,146,083v Miller Feb. 7, 19 2,279,421 Tisdale, Apr. 14, 1942 2,350,265Williams et al. May 30, 1944 2,587,262 Wilson et al. Feb. 28, 1952 OTHERREFERENCES Robbins: Proceedings, Natl. Acad. Sci, US, vol. 28, pages352-5 (1942).

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,030,365 April 17, 1962 Edward F. Rogers et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 7, lines 65 to 68 the formula should appear as shown belowinstead of as in the patent:

column 8 lines 28* 30 the formula should appear as shown below insteadof as in the patent:

II R same column 8 line 31, for "R" read R Signed and sealed this 4thday of September 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

1. A COMPOUND HAVING THE STRUCTURAL FORMULA